# US 12,595,178 B2 · Film-like graphite, manufacturing method for same, and battery using same

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- Number: US 12,595,178 B2
- Document ID: US12595178B2
- Status: Granted
- Kind: B2
- Application number: 18/354,942
- Filed: 2023-07-19
- Published: 2023-11-09
- Granted: 2026-04-07
- Earliest claimed: 2021-01-20
- Assignees: Mitsubishi Chemical Corporation
- Applicants: Mitsubishi Chemical Corporation
- Inventors: Kenji Hirano; Keisuke Wada; Tomoyoshi Yamashita; Norimichi Kawabe; Takuya Suzuki; Miwa Yanagidate; Kouhei Takatani
- Web page: https://patentgrep.com/patent/US12595178B2

## CPC

- C01B 32/205: Preparation
- C01B 32/21: After-treatment
- B32B 7/12: using interposed adhesives or interposed materials with bonding properties
- B32B 9/007: {comprising carbon, e.g. graphite, composite carbon}
- B32B 9/04: comprising such {particular} substance as the main or only constituent of a layer, {which is} next to another layer of {the same or of} a {different material (next to a glass layer B32B17/06; layered products with at least two ceramic layers composed mainly of ceramic B32B18/00)}
- H01M 4/587: for inserting or intercalating light metals
- H01M 4/663: {containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- B32B 2307/202: Conductive
- B32B 2307/302: Conductive
- B32B 2307/72: Density
- B32B 2307/7376: Thickness
- B32B 2457/10: Batteries
- C01P 2002/88: by thermal analysis data, e.g. TGA, DTA, DSC
- C01P 2004/02: obtained by optical microscopy
- C01P 2004/03: obtained by SEM
- C01P 2006/10: Solid density
- C01P 2006/32: Thermal properties
- C01P 2006/40: Electric properties
- H01M 2004/027: {Negative electrodes}
- Y02E 60/10: Energy storage using batteries
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A film-like graphite that satisfies the following condition (1) or condition (2) described below. Condition (1): a graphite crystal orientation degree P is 96% or more with respect to a film plane. Condition (2): a graphite crystal orientation degree P is 94% or more with respect to a film plane and a thickness is 42 μm or more.

## Claims

### Claim 1

A film-like graphite, satisfying condition (1) or condition (2):
Condition (1): a graphite crystal orientation degree P is 96% or more and less than 100% with respect to a film plane, and a thermal conductivity b is 1,550 W/mK or more; or
Condition (2): a graphite crystal orientation degree P is 94% or more and less than 100% with respect to a film plane and a thickness is 42 μm or more and 250 μm or less, and a thermal conductivity b is 800 W/mK or more.

### Claim 2 (depends on 1)

The film-like graphite of claim 1, further satisfying condition (5) and condition (6): condition (6),
Condition (5): when a film thickness is denoted by a in μm, and a thermal conductivity is denoted by b in W/mK, in a direction along a film plane, the film-like graphite satisfies expression (1a)
2,140≤12a+b Expression (1a),
Condition (6): a minimum bending radius measured in a bend test is 16 mm or less.

### Claim 3 (depends on 1)

The film-like graphite of claim 1, having a thickness of 58 μm or more.

### Claim 4 (depends on 1)

The film-like graphite of claim 1, having a thermal conductivity b of 800 W/mK or more in a direction along the film plane.

### Claim 5 (depends on 1)

The film-like graphite of claim 1, having a density of 1.7 g/cm3 or more.

### Claim 6 (depends on 1)

The film-like graphite of claim 1, having an electrical conductivity of 9,000 S/cm or more in a direction along the film plane.

### Claim 7 (depends on 1)

The film-like graphite of claim 1, having a multilayer structure in which a plurality of layers overlap with each other,
wherein the multilayer structure has a width of 40 μm or more and a thickness of 8 μm or more, and
wherein an angle between a direction of each layer constituting the multilayer structure and a direction along the film plane is 20° or less.

### Claim 8 (depends on 7)

The film-like graphite of claim 7, wherein each layer constituting the multilayer structure has a large number of unevenness, and
wherein adjacent layers are in contact with each other at a large number of positions.

### Claim 9 (depends on 7)

The film-like graphite of claim 7, wherein each layer constituting the multilayer structure has a flat surface or a smooth curved surface, and
wherein adjacent layers are in close contact with each other.

### Claim 10 (depends on 1)

The film-like graphite of claim 1, wherein a minimum bending radius measured in a bend test is 16 mm or less.

### Claim 11 (depends on 1)

The film-like graphite of claim 1, wherein, when a pressure of 100 MPa is applied to an entire film plane of the film-like graphite to compress the entire film plane in an environment of 25° C., a Ta/Tb ratio of a film thickness Ta after compression to a film thickness Tb before compression is 0.7 or more.

### Claim 12 (depends on 1)

The film-like graphite of claim 1, wherein in Tension-Free U-shape Folding Test, a folding number is 10,000 or more until breakage, performed at a bending radius R of 2 mm and a bending angle of 180°.

### Claim 13 (depends on 1)

The film-like graphite of claim 1, having a thermal conductivity in a range of from 1 to 20 W/mK in a direction perpendicular to the film plane.

### Claim 14 (depends on 1)

The film-like graphite of claim 1, wherein a surface area/film area ratio of a surface area to a film area is 1.05 or more.

### Claim 15 (depends on 1)

The film-like graphite of claim 1, wherein a layer formed of an adhesive or a pressure-sensitive adhesive is not comprised in the film-like graphite in a film thickness direction.

### Claim 16 (depends on 1)

The film-like graphite of claim 1, wherein an a×b product of a film thickness a in μm, and a thermal conductivity b in W/mK, in a direction along a film plane, is 88,000 or more.

### Claim 17 (depends on 1)

The film-like graphite of claim 1, wherein a number N of a plurality of bright regions obtained from an image in a vertical cross-section of the film-like graphite with respect to a film plane, in which bright parts and dark parts observed in a polarization microscope image are binarized, a film thickness H in μm, and a film width W in μm satisfy expression (7) or (8) and (9)
N/H/W≤0.015 (7),
N/H/W≤0.04 (8),
H≥42 (9).

### Claim 18 (depends on 17)

A lithium-ion secondary battery or an all-solid battery, comprising:
the film-like graphite of claim 17 as a current collector or a negative-electrode active material; and
negative-electrode current collector.

### Claim 19 (depends on 1)

The film-like graphite of claim 1, wherein an average area of a plurality of bright regions obtained from an image in a vertical cross-section of the film-like graphite with respect to a film plane, in which bright parts and dark parts observed in a polarization microscope image are binarized, is 22 μm2 or more, or a film thickness is 42 μm or more and the average area is 9 μm2 or more.

### Claim 20

A film-like graphite, satisfying condition (3) or condition (4):
Condition (3): a film thickness a is 58 μm or more and a thermal conductivity b is 1,550 W/mK or more in a direction along a film plane; or
Condition (4): a film thickness a is 50 μm or more, a thermal conductivity b is 1,550 W/mK or more in a direction along a film plane, and a×b≥100,000.

### Claim 21

A film-like graphite, wherein an a×b product of a film thickness a in μm, and a thermal conductivity b in W/mK, in a direction along a film plane, is 88,000 or more and 500,000 or less, and a thermal conductivity b is 1,550 W/mK or more.

### Claim 22

A film-like graphite, wherein a number N of a plurality of bright regions obtained from an image in a vertical cross-section of the film-like graphite with respect to a film plane, in which bright parts and dark parts observed in a polarization microscope image are binarized, a film thickness H in μm, and a film width W in μm, satisfy expression (7) or (8) and (9)
N/H/W≤0.015 (7),
N/H/W≤0.04 (8),
H≥42 (9).

### Claim 23

A film-like graphite, wherein an average area of a plurality of bright regions obtained from an image in a vertical cross-section of the film-like graphite with respect to a film plane, in which bright parts and dark parts observed in a polarization microscope image are binarized, is 22 μm2 or more, or
wherein a film thickness is 42 μm or more and the average area is 9 μm2 or more.

### Claim 24

A method for manufacturing a film-like graphite, the method comprising:
carbonizing a raw film made of an organic polymer to obtain a carbonized film; and
graphitizing the carbonized film to obtain a graphitized film,
wherein a film-like graphite that has a thermal conductivity of 800 W/mK or more and a minimum bending radius of 16 mm or less according to a bend test is manufactured from the raw film that has a thickness of 150 μm or more and 450 μm or less at a maximum value in a temperature increase range of 60° C. or higher during optional 30 minutes in a temperature increase pattern obtained by a monotonic temperature increase in a temperature increase history of 2,000° C. or higher in the graphitizing.

### Claim 25 (depends on 4)

The method of claim 4, wherein a maximum heating temperature Tmax in the graphitizing is in a range of from 2,400 to 2,900° C.

### Claim 26 (depends on 24)

The method of claim 24, wherein a laminated film in which two or more polymer films made of an organic polymer are bonded to each other by a pressure-sensitive adhesive or an adhesive is used as the raw film.

### Claim 27

A method for manufacturing a film-like graphite, the method comprising:
of carbonizing a raw film, made of an organic polymer and having a thickness of 70 μm or more, to obtain a carbonized film; and
graphitizing the carbonized film to obtain a graphitized film,
wherein the carbonizing comprises heating the raw film in a mixed gas comprising (a-1) acetylene and/or (a2) an acetylene derivative and (b) an inert gas.

### Claim 28 (depends on 27)

The method of claim 27, wherein at least a part of the heating in the mixed gas is carried out at a temperature of Tf or lower,
wherein, in a thermogravimetric analysis in which a measurement sample made of the raw film is heated to 1,000° C. at a temperature increase rate of 10° C./min while flowing nitrogen gas at a flow velocity of 200 mL/min, and a temperature and a weight of the measurement sample are recorded, Tf (C) is a highest temperature among temperatures at which a weight reduction rate, in weight (reduction per unit time,) of the measurement sample observed is 10% or more of a maximum value of the weight reduction rate.

### Claim 29 (depends on 28)

The method of claim 28, wherein a period of 30 minutes or more in which an average temperature increase rate is 5° C./min or less is included in a temperature range of Ts or higher and Tf or lower in a temperature increase pattern obtained by a monotonic temperature increase in a temperature increase history in the heating step in the mixed gas,
where in the thermogravimetric analysis, Ts is a lowest temperature among temperatures of 100° C. or higher at which a weight reduction rate of the measurement sample observed is 0.8% or more of a maximum value of the weight reduction rate.

### Claim 30

A manufacturing method for manufacturing a film-like graphite, the method comprising:
carbonizing a raw film, made of an organic polymer and having a thickness of 120 μm or more, to obtain a carbonized film;
graphitizing the carbonized film to obtain a graphitized film having a density of less than 1.7 g/cm3; and
compressing or rolling the graphitized file to obtain the film-like graphite, having a density of 1.7 g/cm3
wherein an Sg/Sm ratio of an area Sg of the graphitized film to an area Sm of the raw film is 0.8 or more.